This disclosure is generally directed to members like xerographic imaging members; photoreceptors, photoconductors, and the like. More specifically, the present disclosure is directed to rigid, multilayered flexible, belt imaging members, or devices comprised of an optional supporting medium like a substrate, a fatty ester, and more specifically, a vulcanized fatty ester photogenerating layer, and a charge transport layer including a plurality of charge transport layers, such as a first charge transport layer and a second charge transport layer, an optional adhesive layer, an optional hole blocking or undercoat layer, and an optional overcoating layer. At least one in embodiments refers, for example, to one, to from 1 to about 10, to from 2 to about 7; to from 2 to about 4, to two, and the like. Moreover, the fatty ester can be added to the photogenerating layer instead of being dissolved in the photogenerating layer solution.
Yet more specifically, there is disclosed a photoconductor comprised of a supporting substrate, a vulcanized fatty ester, such as, for example, those esters as illustrated hereinafter, containing photogenerating layer, a charge transport layer, or charge transport layers, such as a first pass charge transport layer, a second pass charge transport layer to primarily permit excellent and minimal undesirable ghosting characteristics, reduced paper edge ghosting (PEG), as compared to a photoconductor that does not contain the fatty ester; excellent photoconductor photosensitivities, and an acceptable, and in embodiments a low Vr; and minimization or prevention of Vr cycle up.
The photoconductors disclosed herein possess a number of advantages, such as in embodiments, the minimization of undesirable ghosting on developed images, such as xerographic images, including improved ghosting at various relative humidities; excellent cyclic and stable electrical properties; minimal charge deficient spots (CDS); compatibility with the photogenerating and charge transport resin binders; and acceptable lateral charge migration (LCM) characteristics, such as for example, excellent LCM resistance.
Ghosting refers, for example, to when a photoconductor is selectively exposed to positive charges in a number of xerographic print engines when some of the charges enter the photoconductor and manifest themselves as a latent image in the next printing cycle. This print defect can cause a change in the lightness of the half tones, and is commonly referred to as a “ghost” that is generated in the previous printing cycle. An example of a source of the positive charges is the stream of positive ions emitted from the transfer corotron. Since the paper sheets are situated between the transfer corotron and the photoconductor, the photoconductor is shielded from the positive ions from the paper sheets. In the areas between the paper sheets, the photoconductor is fully exposed, thus in this paper free zone the positive charges may enter the photoconductor. As a result, these charges cause a print defect or ghost in a half tone print if one switches to a larger paper format that covers the previous paper print free zone.
Excellent cyclic stability of the photoconductor refers, for example, to almost no or minimal change in a generated known photoinduced discharge curve (PIDC), especially no or minimal residual potential cycle up after a number of charge/discharge cycles of the photoconductor, for example about 100 kilocycles, or xerographic prints of, for example, from about 80 to about 100 kiloprints. Excellent color print stability refers, for example, to substantially no or minimal change in solid area density, especially in 60 percent halftone prints, and no or minimal random color variability from print to print after a number of xerographic prints, for example 50 kiloprints.
Also disclosed are methods of imaging and printing with the photoconductor devices illustrated herein. These methods generally involve the formation of an electrostatic latent image on the imaging member, followed by developing the image with a toner composition comprised, for example, of thermoplastic resin, colorant, such as pigment, charge additive, and surface additive, reference U.S. Pat. Nos. 4,560,635; 4,298,697 and 4,338,390, the disclosures of which are totally incorporated herein by reference, subsequently transferring the image to a suitable substrate, and permanently affixing the image thereto. In those environments wherein the device is to be used in a printing mode, the imaging method involves the same operation with the exception that exposure can be accomplished with a laser device or image bar. More specifically, flexible belts disclosed herein can be selected for the Xerox Corporation iGEN3® machines that generate with some versions over 100 copies per minute. Processes of imaging, especially xerographic imaging and printing, including digital, and/or color printing, are thus encompassed by the present disclosure. The imaging members are in embodiments sensitive in the wavelength region of, for example, from about 400 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source. Moreover, the imaging members of this disclosure are useful in high resolution color xerographic applications, particularly high speed color copying and printing processes.